# Library usage
`dmarc-report-parser` exposes a small, focused API for parsing DMARC aggregate
feedback reports from their XML representation as defined in
[RFC 7489 Appendix C](https://www.rfc-editor.org/rfc/rfc7489#appendix-C).
## Parsing a report
The primary entry point is [`parse`], which accepts an XML string and returns a
[`Report`]:
```rust
let xml = r#"<?xml version="1.0" encoding="UTF-8"?>
<feedback>
<report_metadata>
<org_name>Example Corp</org_name>
<email>dmarc@example.com</email>
<report_id>abc123</report_id>
<date_range>
<begin>1609459200</begin>
<end>1609545600</end>
</date_range>
</report_metadata>
<policy_published>
<domain>example.com</domain>
<adkim>r</adkim>
<aspf>r</aspf>
<p>none</p>
<sp>none</sp>
<pct>100</pct>
</policy_published>
<record>
<row>
<source_ip>192.0.2.1</source_ip>
<count>5</count>
<policy_evaluated>
<disposition>none</disposition>
<dkim>pass</dkim>
<spf>pass</spf>
</policy_evaluated>
</row>
<identifiers>
<envelope_from>example.com</envelope_from>
<header_from>example.com</header_from>
</identifiers>
<auth_results>
<spf>
<domain>example.com</domain>
<result>pass</result>
</spf>
</auth_results>
</record>
</feedback>"#;
let report = dmarc_report_parser::parse(xml).unwrap();
assert_eq!(report.report_metadata.org_name, "Example Corp");
```
If you have raw bytes instead of a string, use [`parse_bytes`]:
```rust
# let xml_bytes: &[u8] = b"<?xml version=\"1.0\"?>
# <feedback>
# <report_metadata>
# <org_name>Test</org_name><email>t@e.com</email><report_id>1</report_id>
# <date_range><begin>0</begin><end>0</end></date_range>
# </report_metadata>
# <policy_published><domain>e.com</domain><p>none</p><sp>none</sp><pct>100</pct></policy_published>
# <record>
# <row><source_ip>127.0.0.1</source_ip><count>1</count>
# <policy_evaluated><disposition>none</disposition><dkim>pass</dkim><spf>pass</spf></policy_evaluated>
# </row>
# <identifiers><envelope_from>e.com</envelope_from><header_from>e.com</header_from></identifiers>
# <auth_results><spf><domain>e.com</domain><result>pass</result></spf></auth_results>
# </record>
# </feedback>";
let report = dmarc_report_parser::parse_bytes(xml_bytes).unwrap();
```
## Trait-based parsing
[`Report`] implements [`FromStr`](std::str::FromStr), [`TryFrom<&str>`], and
[`TryFrom<&[u8]>`] so you can use whichever style fits your code:
```rust
use std::str::FromStr;
use dmarc_report_parser::Report;
# let xml = r#"<?xml version="1.0"?>
# <feedback>
# <report_metadata>
# <org_name>Test</org_name><email>t@e.com</email><report_id>1</report_id>
# <date_range><begin>0</begin><end>0</end></date_range>
# </report_metadata>
# <policy_published><domain>e.com</domain><p>none</p><sp>none</sp><pct>100</pct></policy_published>
# <record>
# <row><source_ip>127.0.0.1</source_ip><count>1</count>
# <policy_evaluated><disposition>none</disposition><dkim>pass</dkim><spf>pass</spf></policy_evaluated>
# </row>
# <identifiers><envelope_from>e.com</envelope_from><header_from>e.com</header_from></identifiers>
# <auth_results><spf><domain>e.com</domain><result>pass</result></spf></auth_results>
# </record>
# </feedback>"#;
// Using FromStr
let report = Report::from_str(xml).unwrap();
// Using str::parse
let report: Report = xml.parse().unwrap();
// Using TryFrom
let report = Report::try_from(xml).unwrap();
```
## Error handling
Both [`parse`] and [`parse_bytes`] return `Result<Report, Error>`. The [`Error`]
type has two variants:
- **`Error::Parse`** — the XML is malformed or does not match the DMARC report
schema.
- **`Error::Utf8`** — the input bytes are not valid UTF-8 (only from
`parse_bytes` / `TryFrom<&[u8]>`).
## Working with the report
Once parsed, you can access every field of the RFC 7489 schema through the
strongly-typed structs:
```rust
# let xml = r#"<?xml version="1.0"?>
# <feedback>
# <report_metadata>
# <org_name>Test</org_name><email>t@e.com</email><report_id>1</report_id>
# <date_range><begin>0</begin><end>0</end></date_range>
# </report_metadata>
# <policy_published><domain>e.com</domain><p>none</p><sp>none</sp><pct>100</pct></policy_published>
# <record>
# <row><source_ip>127.0.0.1</source_ip><count>1</count>
# <policy_evaluated><disposition>none</disposition><dkim>pass</dkim><spf>pass</spf></policy_evaluated>
# </row>
# <identifiers><envelope_from>e.com</envelope_from><header_from>e.com</header_from></identifiers>
# <auth_results><spf><domain>e.com</domain><result>pass</result></spf></auth_results>
# </record>
# </feedback>"#;
use dmarc_report_parser::{parse, DmarcResult};
let report = parse(xml).unwrap();
// Iterate over records and check results
for record in &report.records {
let ip = &record.row.source_ip;
let count = record.row.count;
let dkim = record.row.policy_evaluated.dkim;
let spf = record.row.policy_evaluated.spf;
if dkim == DmarcResult::Fail || spf == DmarcResult::Fail {
println!("{ip} sent {count} message(s) that failed DMARC");
}
}
```